I would like to do one in mid-atlantic region. I'd offer to organize it myself but I don't think there's enough decent unpaved roads in NJ (unless you like the sand of the pinelands) but I suspect there are places not too far away in Pennsylvania where one could make this happen. People talk about a place called "upstate New York" that sounds like it might have potential, but I've never really figured out where that is. Nowhere near "western New York" which, come to think of it, is a very pretty place that might have some potential.
The one in Montana looks totally cool. I'd love to do it. But getting to Montana is like a two day drive. And I don't drive if I can help it.
So organize a race down the C&O Canal Towpath! If 1840 isn't C&V, I don't know what would be.